JDK, the not so hidden treasures

JDK not so hidden treasuresAndrzej Grzesik

andrzej grzesik@ags313

[email protected]

andrzejgrzesik.info

@javazone @ags313please tweet!

questions?just ask!

java

$JAVA_HOME/bin

tl;dr: log gc please

log gc :-)

when things go…

does it run?

top // htop

every known problem becomes completely new

when you add “in Java”

stolen from: @mryapee

jpsinstead of ps

jpsinstead of ps

jps -lvmJava ProcesseS LoVe Memory

jar

jar -tf

jinfo

demo

javac

javacjust the compiler

javap

jmapinstead of pmap

and jhat

demo

stacktraces :)

kill -3 <pid>

demo

caveat ;-)

caveat ;-)prints to STDOUT of the running process

jstack

caveatsonly at safepoints, one thread at a time

demo

jstat

jstat <metric> <options> PID <interval> <count>

demo

custom optionshttp://hg.openjdk.java.net/jdk9/jdk9/jdk/file/d49e247dade6/src/jdk.jcmd/share/

classes/sun/tools/jstat/resources/jstat_options

jstatd

jstatdexposes your processes

jcmd

jvisualvm

jmxsh

jmxtermhttp://wiki.cyclopsgroup.org/jmxterm

http://code.google.com/p/jmxsh/

and more

questions?just shoot!

Thank you!